[PATCH 2/3] store external device tree as file

[Sascha Hauer <s.hauer@pengutronix.de>]

When barebox is chainloaded from another bootloader it usually gets
passed a device tree from the previous bootloader. While this external
device tree is normally not used by barebox, its contents can still be
interesting, so store the device tree at /external-devicetree when
found. This needs board support to pass the external device tree in
handoff data, i.e. a board has to call
handoff_data_add(HANDOFF_DATA_EXTERNAL_DT, dtb, size);

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 common/startup.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/common/startup.c b/common/startup.c
index b311b77418..abdc0c2db0 100644
--- a/common/startup.c
+++ b/common/startup.c
@@ -40,6 +40,8 @@
 #include <net.h>
 #include <efi/efi-mode.h>
 #include <bselftest.h>
+#include <pbl/handoff-data.h>
+#include <libfile.h>
 
 extern initcall_t __barebox_initcalls_start[], __barebox_early_initcalls_end[],
 		  __barebox_initcalls_end[];
@@ -246,6 +248,8 @@ static int run_init(void)
 	struct stat s;
 	glob_t g;
 	int i, ret;
+	size_t size;
+	void *ext_dtb;
 
 	setenv("PATH", "/env/bin");
 	export("PATH");
@@ -289,6 +293,10 @@ static int run_init(void)
 		globfree(&g);
 	}
 
+	ext_dtb = handoff_data_get_entry(HANDOFF_DATA_EXTERNAL_DT, &size);
+	if (ext_dtb)
+		write_file("/external-devicetree", ext_dtb, size);
+
 	/* source matching script in /env/bmode/ */
 	bmode = reboot_mode_get();
 	if (bmode) {

-- 
2.39.5